Apparatus for making corrugated paper board

ABSTRACT

Apparatus for making corrugated paper board of the type having at least two facing sheets. The contacting component webs of supply material are fed along heating plates to adhesively secure them together. To prevent board warpage because of the outer (bottom) facing sheet&#39;&#39;s being drier than the inner (top) sheet, moisture is added to the outer sheet after the board leaves the heating plates, to equalize the moisture content of the two sheets.

United States Patent 1151 3,654,032 Kruglinski et a1. [45] Apr. 4, 1972[54] APPARATUS FOR MAKING 3,004,880 10/1961 Lord ..156/64 CORRUGATEDPAPER BOARD 3,217,425 11/1965 Nikkel ..156/588 3,467,541 9/1969 Aronssonet al. 162/207 [721 lnvemors= Frank Krug'inski' Begen; 3,510,374 5/1970Walker ..156/64 Joseph A. Miller, Englewood, both of NJ.

FOREIGN PATENTS OR APPLICATIONS 221,712 7/1957 Australia 162/204 PrimaryExaminer-Benjamin A. Borchelt Assistant Examiner-H. J. TudorAttorney-Samuelson and Jacob [5 7] ABSTRACT Apparatus for makingcorrugated paper board of the type having at least two facing sheets.The contacting component webs of supply material are fed along heatingplates to adhesively secure them together. To prevent board warpagebecause of the outer (bottom) facing sheets being drier than the inner(top) sheet, moisture is added to the outer sheet after the board leavesthe heating plates, to equalize the moisture content of the two sheets.

3 Claims, 3 Drawing Figures [73] Assignee: General Corrugated MachineryCo., Inc.,

PalisadesPark, NJ.

[22] Filed: Sept. 12, 1969 [21] Appl. No.: 857,306

[52] U.S.Cl ..l56/470, 156/205, 156/590 [51] Int. Cl. ..B3lf1/20 [58]Field of Search ..156/470, 64, 462, 378, 459,

[56] References Cited UNITED STATES PATENTS 2,069,063 l/1937 Gibbs..162/204 2,993,828 7/1961 Krunsick, Jr. et a1 ..162/204 20 a O :1 o

Patented April 4, 1972 3,654,032

2 Sheets-Sheet 1 mvcmmps FRANK Q K uqLmcaKr JO$EPH A M\| L ER M 1 0 Few3,54,032 Patented April 4, 1972 2 Sheets-Sheet z QTTOPN v5 V heatingmeans which bonds APPARATUS FOR MAKING CORRUGATED PAPER BOARD Inmanufacturing corrugated paper board, such as is used for shipping caseswhich are generally made ofa central fluted or corrugated core layerbonded to outer, opposed face sheets, the usual way of effecting thisbonding is by using a starch base paste. The board is passed over aseries of heated plates to cause the starch to gel and harden,completing the bond. However, this operation tends to dry out the bottomface sheet, i.e., the sheet nearest the heating plates. The heat drivesthe moisture out of the bottom sheet into the top sheet. Also, themoisture driven out of the starch paste (to cause it to bond) likewisesettles in the corrugated core layer and top facing sheet. Because ofthis considerable resulting moisture differential between the twosheets, the sheet board warps upon drying after leaving the board makingmachine.

To overcome the problems of feeding warped board in subsequentoperations, it has been necessary to stack the cut sheets so thatalternate handfuls are reversed. Automation of this alternate stackinghas not been economically practical, requiring expensive manualstacking.Furthermore, automatic feeding of such alternately arranged stacks intosubsequent machines has been difficult, consequently making it necessaryto feed the sheets manually.

In accordance with the present invention, after leaving the heatingplates the board passes over moisturizing means for adding moisture tothe lower facing sheet to balance the moisture content of the lower andupper sheets. Preferably, the moisturizing means comprises one or moremoisturizing chests. The chest or chests may be incorporated in themachine in place of or in addition to the final heating plate or plates.The chest comprises a number of compartments arranged in a row acrossthe width of the longitudinally fed board. Each compartment contains anupwardly extending water supply pipe terminating in an atomizer head forspraying water onto the bottom facing sheet passing over the chest. Theamount of water sprayed may be controlled by moisture sensors whichsense the moisture content of the sheets. Additional control means mayvary the volume of water sprayed in accordance with the speed of themachine operation.

It is therefore an important object of the present invention to preventwarpage in the manufacture of faced corrugated paper board.

It is a further object to prevent such warpage by equalizing themoisture content ofthe facing sheets of the board.

It is a further object to prevent such warpage by adding moisture to thebottom facing sheet after the board has left the the board componentstogether,

The above, and other objects, advantages, features and uses of theinvention will become apparent to those skilled in the art from thefollowing detailed description of a preferred embodiment of theinvention when read in conjunction with the accompanying drawingswherein:

FIG. 1 is a side elevational view of a corrugated board making machinein which the invention is incorporated;

FIG. 2 is an enlarged longitudinal sectional view of a portion ofthemachine ofFlG. 1;

FIG. 3 is an enlarged perspective view showing the moisturizing unit ofthe machine.

Referring now to the drawings, and particularly FIG. 2 thereof, thereference numeral 2 denotes the corrugated paper board. The boardcomprises a fluted paper center or core 4 to the opposed high points orpeaks of which are adhesively secured opposed top and bottom face sheets6 and 8. The adhesive most commonly used is a starch base adhesive.

Referring to FIG. 1, this figure shows a conventional machine for makingthe corrugated board, modified in accordance with the present invention.The material flow is from left to right in FIG. 1. The material suppliedto the machine for the manufacture of the board comprises two webs. Webcomprises the fluted core 4 and the upper face sheet 6 adhered thereto.The lower peaks of core 4 have a coating of starch adhesive by which thetwo webs are to be bonded together. The other web consists of the lowerface sheet 8, to be bonded to the fluted core 4 in the machine. Web 10is made in accordance with any well-known technique.

Webs 8 and 10 are fed and guided, by suitably arranged rollers, intocontacting relation at the first of a number of heating plates ofconventional construction. That is to say, the heating plates arehollow, and steam is fed into them to heat them. In FIG. 1, the numerals12 (a-n) designate the heating plates, the numerals 12a and 12nrespectively denoting the first and the last of the entire series ofheating plates. The contacting webs 8 and 10 are fed along the series ofheating plates to heat the starch adhesive on the lower peaks of thecore 4 to cause it to gel and harden, thereby bonding the bottom facingsheet 8 to the fluted core 4.

The machine has opposed spaced longitudinal side frames 14, 16 on whichthe heating plates are supported.

The webs 8 and 10 are held in close contact with the heating plates by aballastbelt 18. A series of overlying ballast rollers 20 rest on ballastbelt 18 to press the belt against the webs 8, 10 being processed, sothat the webs firmly contact one another and lower face sheet 8 is inform heat exchange contact with the heating plates. I

At the discharge end of the machine, a lower belt 22 driven in anysuitable fashion by a drive roller 24 supports the completed corrugatedpaper board. Belts 18 and 22, between which the board is held, feed theboard from the machine. A series of opposed, cooperating pairs of guiderollers 26, 28 is provided, between which belts 18 and 22 pass.

The machine as described to this point is substantially conventional. Asdiscussed earlier, since the lower facing sheet 8 is closest to theheating plates, most of the moisture is driven out of this sheet intothe top facing sheet 6. Additionally, the heating of the adhesive (tobond the lower sheet 8 to the fluted core 4) causes the moisturecontained in the adhesive likewise to be driven into the upper sheet.Thus, there is a considerable moisture content differential between theupper and lower facing sheets resulting in the completed board beingwarped after it dries.

In accordance with the present invention, this objectionable warping isavoided by providing the machine with means for adding moisture to thelower facing sheet 8 after the board has left the heating plates, toequalize the moisture content of the two facing sheets, as will now bedescribed in detail.

Located immediately after, i.e., downstream of, the last heating plate12n is a moisturizing chest 30 over which the board passes. In fact, themoisturizing chest can replace the last heating plate in commerciallyavailable machines. The chest is best seen in FIG. 3. It includes achannel shaped, main member 32, supported on the machine longitudinalframe plates 14, 16. Longitudinal partition plates 33 subdivide thechest into a series of compartments 34, the series being transverse tothe longitudinal feeding movement of the paperboard through the machine.Extending upwardly into each compartment is a water supply line 36 whichterminates in an atomizer head 38 arranged to spray water onto the lowerfacing sheet 8 continuously passing overhead. An automaticallyadjustable valve 40, which may also be manually adjustable, controls theflow in each water line 36.

The valves 40 are adapted to be automatically controlled as follows:

There are provided sensors content of the two webs 8 and well-known,

42 for measuring the moisture 10. These sensors may be of anyconventional type having a signal output representative of the moisturecontent measured. The sensors 42 are located at the input end of themachine, as shown in FIG. 1. One transverse row of sensors senses themoisture content of lower facing sheet web 8. Each of these sensors islocated at a transverse position corresponding to a related one of theatomizer spray heads 38. Additionally, there may be provided a row ofsimilarly transversely positioned auxiliary sensors 42 above web 10 formeasuring the moisture content of the upper facing sheet.

across the entire width of the board.

Control means 44 is also provided for valves 40 to increase and decreasethe water flow in accordance with any changes made in the speed of themachine operation. If the board speed is increased, more water may haveto be sprayed onto lower facing sheet 8; and conversely, a decrease inthe boards speed may necessitate a decrease in the amount of appliedwater, or vice-versa, depending on conditions.

The speed sensing input to control unit 44 may be taken off any suitablepoint in the machine, for example, the shaft of drive roller 24 of lowerbelt 22, as shown in FIG. 1. it will be understood that the details ofconstruction of control unit 44, as well as of sensors 42, form no partofthe present invention. Such devices, per se, are of well-known andreadily available construction.

lf board having a width less than the full width capacity of the machineis to be fed, the unneeded compartments 34 of moisturizing chest 30 canbe blocked off or disabled by placing louvers or cover plates 46 overthem, as shown in FIG. 3.

The compartments 34 may be provided with suitable drain run-off means toremove accumulated water.

After continuously fed board leaves the moisturizing chest by thefeeding belts 18, 22, feed and therefore a more uniform length of thecut-off sheets because of the aforementioned increased abrasiveness andfriction the lower sheet will snag and peel back, causing a break. Thenthe machine has to be shut down to clear the break and the webs must berethreaded through the machine.

a greater number of layers, e.g., three facing sheets with a fluted corebetween each of each two adjacent sheets.

Also, while only one moisturizing chest has been shown, a

property or privilege is claimed are defined as follows:

1. In a machine for making corrugated paper board of the type having atleast one fluted core and at least two spaced facing sheets, from atleast two webs of material, each of said webs comprising a respectiveone of said facing sheets:

means defining a feed path in said machine; means for feeding said websalong said feed path; means for bonding said two webs together to formsaid board, said bonding means comprising heating means; said heatingmeans being at a first location along said feed ath; msisturizing meansfor adding moisture to the drier one of said two facing sheets toequalize the moisture content of said two facing sheets to preventwarping of said board; said moisturizing means being at a secondlocation along said feed path downstream of said heating means andcomprising: a plurality of compartments at several locations along thewidth of the sheet; a plurality of spraying devices,

ing device disposed in a separate one of said there being a separatespraycompartments to thereby spray water onto said one facing sheet atsaid several locations along the width ofthe sheet..

2. The combination according to claim 1, including:

means for selectively disabling at least one of said spraying devices.

3. The combination according to claim 2, wherein:

said disabling means comprises cover means for the compartment in whichsaid one spraying device is disposed.

1. In a machine for making corrugated paper board of the type having atleast one fluted core and at least two spaced facing sheets, from atleast two webs of material, each of said webs comprising a respectiveone of said facing sheets: means defining a feed path in said machine;means for feeding said webs along said feed path; means for bonding saidtwo webs together to form said board, said bonding means comprisingheating means; said heating means being at a first location along saidfeed path; moisturizing means for adding moisture to the drier one ofsaid two facing sheets to equalize the moisture content of said twofacing sheets to prevent warping of said board; said moisturizing meansbeing at a second location along said feed path downstream of saidheating means and comprising: a plurality of compartments at severallocations along the width of the sheet; a plurality of spraying devices,there being a separate spraying device disposed in a separate one ofsaid compartments to thereby spray water onto said one facing sheet atsaid several locations along the width of the sheet.
 2. The combinationaccording to claim 1, including: means for selectively disabling atleast one of said spraying devices.
 3. The combination according toclaim 2, wherein: said disabling means comprises cover means for thecompartment in which said one spraying device is disposed.